Andrew Hudson, whose recent article on BFS over at ARSTechnicaintrigued us, shares with us some thoughts on the state of apps on Haiku. It turns out there are several repositories with a vast array of applications ready-to-go for your new Haiku install.

edit:
I hope Blender (the 3D graphics app) will get Haiku support back.

I'm not so sure about pacman, I'd rather have a graphical package manager directly written for haiku. As for Blender, indeed I'd love to see that. Personally, with Blender and Inkscape ported I would be able to do alot more productively in Haiku. Until we get 3d hardware acceleration in Haiku Blender will likely not be very useful other than for rendering, but Inkscape should perform well.

aljen made a more recent port than that but it was integrated into the haiku build system I don't know if the patch is still around.... it might be worth asking

Pacman itself wouldn't be ideal... but it is just a frontend

what would be neat is to the pacman libraries with a native haiku frontend... some small and simple applications can be installed via the packagefs system which is in development. However, large complex programs will probably always need a more normal package manager for which libpacman fits the bill quite nicely since there are already multiple projects using it it will probably be well supported in the future as well.

libpacman + BeGui could also be complemented by combining it with haikuports so that similar to arch some packages could be rolling release for instance Web+ updates or the latest and greatest blender... which probably wouldn't mean a complete rebuild of the system.

Pacman is a good place to start with, but I think the package manager should have the source code/package management abilities of yaourt to be begin with.
Packages are nice, but the ability to easily compile applications from source with specific options enabled is really nice. Source compiles from ports is one of the reasons I love FreeBSD, and I would like to see Haiku make a serious effort to put binary packages and source code tarballs on equal terms.